[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111130
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN MAR 11 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N10W 4N21W 2N28W EQ36W 1S43W AND
INTO NE BRAZIL NEAR 3S46W. SCATTERED MODERATE CONVECTION IS
WITHIN 90 NM N OF THE AXIS BETWEEN 22W-30W. SCATTERED SHOWERS
AND TSTMS ARE WITHIN 60 NM EITHER SIDE E OF 22W.

...DISCUSSION...

GULF OF MEXICO...
WEAK SFC HIGH PRES RIDGING CONTINUES TO DOMINATE MUCH OF THE
GULF. THE VERY WEAK SFC TROUGH THAT HAS BEEN STATIONARY FOR THE
PAST 36-48 HOURS IN THE CENTRAL GULF HAS NOW DISSIPATED...OR
AT LEAST LIFTED OFF THE SFC. LIGHT TO MODERATE ELY WINDS COVER
THE REGION THIS MORNING BUT THEY WILL LIKELY INCREASE LATER
TODAY AND MON AS A STRONG HIGH PRES SYSTEM IN THE UPPER MIDWEST
SURGES SE. IN THE UPPER LEVELS...STRONG ZONAL FLOW DOMINATES
MUCH OF THE BASIN BETWEEN RIDGING EXTENDING N FROM THE SW
CARIBBEAN AND A COUPLE OF SHORTWAVE TROUGHS PUSHING THROUGH THE
CONUS AND OFF THE E COAST. THESE STIFF WINDS ARE ADVECTING
ABUNDANT UPPER LEVEL MOISTURE/HIGH CLOUDS FROM THE EPAC ACROSS
CENTRAL MEXICO INTO THE GULF MAINLY S OF 26N. DRY STABLE AIR
ALOFT COVERS MOST OF THE REGION N OF 26N MAINTAINING FAIR
WEATHER. OVER THE NEXT FEW DAYS...THE SYSTEM OF MOST INTEREST IS
THE UPPER SHORTWAVE TROUGH THAT IS CURRENTLY OVER COLORADO AND
NEW MEXICO. GFS SHOWS THIS SYSTEM CUTTING OFF SHORTLY...IN FACT
WV IMAGES SHOW THIS PROCESS ALREADY UNDERWAY...AND MOVING LITTLE
OVER THE NEXT COUPLE OF DAYS. THIS WILL LIKELY INCREASE MOISTURE
IN THE W GULF AS THE UPPER FLOW VEERS SWLY.

CARIBBEAN...
AN UPPER LEVEL HIGH CENTERED IN THE SW CARIB NEAR 12N75W IS THE
MAIN WEATHER FEATURE IN THE REGION. STRONG WLY FLOW ON THE NRN
PERIPHERY OF THE RIDGE IS ADVECTING A SWATH OF HIGH CLOUDS
ACROSS THE S GULF...THE YUCATAN PENINSULA AND CUBA. ELSEWHERE
QUIET WEATHER PERSISTS WITH PLENTY OF DRY STABLE AIR ALOFT IN
PLACE. SLIGHT UPPER LEVEL TROUGHING LIES ABOVE THE LESSER
ANTILLES...BUT THE ONLY EFFECT OF THIS IS AN EVEN MORE STABLE
ENVIRONMENT DUE TO UPPER CONFLUENT/SUBSIDENT FLOW. FAIR WEATHER
AND TYPICAL ISOLATED TRADE WIND SHOWERS IS THE THEME ACROSS THE
SEA TODAY. THERE ARE VERY SMALL CLUSTERS OF MODERATE CONVECTION
OVER COLOMBIA AND THE ATLC COASTAL WATERS OF COSTA RICA AND W
PANAMA ENHANCED BY A DIFFLUENT PATTERN ALOFT. MORE OF THE
SAME...TRANQUIL WEATHER AND MODERATE TO FRESH TRADES...IS THE
FORECAST FOR THE NEXT COUPLE OF DAYS.

WESTERN ATLANTIC...
MESSY WEATHER CONTINUES FOR PARTS OF THE REGION. THE SYNOPSIS
PRODUCING THIS UNSETTLED WEATHER REMAINS FAIRLY COMPLEX AND FAST
EVOLVING...I WILL DO MY BEST TO EXPLAIN IT. STARTING IN THE
UPPER LEVELS...A SHORTWAVE TROUGH LIES ALONG 70W N OF 25N. MID
TO UPPER LEVEL ENERGY/VORTICITY ASSOCIATED WITH THIS SHORTWAVE
IS PRODUCING A SPIN IN THE CLOUDS AND LIKELY SOME SCATTERED
SHOWERS N OF 28N BETWEEN 68W-72W. SWLY UPPER LEVEL FLOW TO THE E
OF THE AXIS ALONG WITH A HIGHLY DIFFLUENT PATTERN ARE
SIGNIFICANT FACTORS FOR THE DEEPER MOISTURE FURTHER E. THE
CONTRIBUTING SFC FACTORS...AS OF 09 UTC...CONSIST OF A
INTENSIFYING AREA OF LOW PRES JUST E OF BERMUDA AND AN
ASSOCIATED COLD FRONT WHICH EXTENDS SWD FROM THE LOW TO 27N68W.
A SFC TROUGH...LACKING MUCH THERMAL GRADIENT...CONTINUES S FROM
THERE TO HISPANIOLA. THIS PATTERN IS SIGNIFICANTLY DIFFERENT
FROM JUST 3 HOURS AGO AS IT IS NOW CLEAR THAT THE LOW NEAR
BERMUDA HAS BECOME THE DOMINATE FEATURE WITH THE MOISTURE SWATH
MOLDING INTO A BAROCLINIC LEAF PATTERN. A WARM FRONT EXTENDS EWD
FROM THE LOW NEAR BERMUDA ALONG 32N/33N. ALL OF THESE ELEMENTS
ARE AIDING IN PRODUCING A SWATH OF DEEP MOISTURE N OF 28N
BETWEEN 56W-66W AND FROM 19N-28N BETWEEN 62W-68W. IN
ADDITION...STRONG WINDS ARE A HIGH CONCERN AS A TIGHT SFC
PRESSURE GRADIENT EXISTS BETWEEN THE LOW AND A 1037 MB HIGH NEAR
39N48W. UP TO GALE FORCE WINDS ARE OCCURRING N OF 29N BETWEEN
58W-64W. LOOKING AHEAD...THE LOW PRES SYSTEM IS EXPECTED TO
CONTINUE DEEPENING AS IT TRACKS RATHER QUICKLY TO THE
N...EXPECTED TO BE WELL N OF THE DISCUSSION AREA TONIGHT.
HOWEVER...THE ASSOCIATED TRAILING TROUGH WILL REMAIN IN THE
REGION FOR THE NEXT COUPLE OF DAYS.

EASTERN ATLANTIC...
STRONG HIGH PRESSURE RIDGING CONTINUES TO DOMINATE THE SFC
PATTERN ACROSS MUCH OF THE CENTRAL AND EASTERN ATLC. THIS HIGH
IS PRODUCING MODERATE TO FRESH TRADE WINDS AND FAIR WEATHER
ACROSS A GOOD PORTION OF THE AREA. IN THE MID AND UPPER
LEVELS...STRONG RIDGING ALSO DOMINATES WITH A HIGH CENTER NEAR
21N31W. DRY AND STABLE AIR ALOFT RESULTING IN STRONG SUBSIDENCE
IS AIDING IN THE WIDESPREAD FAIR WEATHER. THE TRADE WINDS ARE
SET TO PICK UP AGAIN FROM W TO E STARTING TODAY INTO NEXT WEEK
AS STRONG HIGH PRES REBUILDS E ACROSS THE ATLC OCEAN. UPPER
RIDGING WILL ALSO REMAIN IN CONTROL PROMOTING THE CONTINUATION
OF FAIR WEATHER.

$$
CANGIALOSI



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